1. Technical Field
Exemplary embodiments of this disclosure relate to a toner cartridge to store powder such as toner, and to an image forming apparatus incorporating the toner cartridge.
2. Description of the Related Art
Image forming apparatuses are used as, for example, copiers, printers, facsimile machines, and multi-functional devices having at least one of the foregoing capabilities. As one type of image forming apparatus, electrophotographic image forming apparatuses are known. Such an electrophotographic image forming apparatus may have a toner cartridge to supply toner to form a toner image. The toner cartridge is replaced when toner is exhausted due to toner consumption by printing (see, for example, U.S. Pat. No. 812,637-B, JP-2001-201931-A, JP-2006-208433-A, and JP-2008-197636-A). It is therefore preferable to increase the toner capacity of a toner cartridge in order to prolong the product life. However, an increase in the toner capacity typically accompanies an increase in size of the toner cartridge and also an increase in size of an image forming apparatus in which the toner cartridge is mounted. Accordingly, there is a demand for a toner cartridge having a large toner capacity and a space-saving design (small wasteful space).
When a large amount of toner remains in a container before replacement of a toner cartridge, this means that an actual toner capacity is decreased by the amount of the residual toner quantity. Therefore, there is a demand for reduction in residual toner quantity in addition to the enlargement of toner capacity.
On the other hand, a toner cartridge having a laterally long cross section in which two rotary agitation members are provided has been proposed (see, for example, U.S. Pat. No. 812,637-B) to enlarge the capacity by increasing a lateral width dimension in a cross section of a toner container of the toner cartridge. In this type, it is to be noted that rotation trajectories of the two rotary agitation members may be placed apart from each other, or a toner transport screw may be placed in a space between the two rotary agitation members or a space at an end of the toner container.
Such a toner cartridge in which two rotary agitation members are placed apart from each other, however, has a relatively large size of a toner container in the lateral width direction viewed from a rotation axis direction of the rotary agitation members.